[Plugin: Simple Tags] [Simple tags 1.7.4.4] warning message before all excerpt post except the firt

hello I have this warning message before all my post excerpt form index page, except the first excerpt.
Warning: array_keys() [function.array-keys]: The first argument should be an array in [the_path]/wp-content/plugins/simple-tags/inc/client.php on line 1310

Warning: shuffle() expects parameter 1 to be array, null given in [the_path]/wp-content/plugins/simple-tags/inc/client.php on line 1311

Warning: Invalid argument supplied for foreach() in [the_path]/wp-content/plugins/simple-tags/inc/client.php on line 1312

what does it mean? how I can fixe it?

thanks for your answers.
Benoit
be friendly I’m not english 😉